Methods for vacuum evacuation of  waste foam/gas from an electrocoagulation unit during effluent treatment

ABSTRACT

Apparatus and method are disclosed for integrated waste foam/gas evacuation from an electrocoagulation unit. The electrocoagulation unit has a primary electrocoagulation reaction chamber with processing electrodes maintained therein. A flotation chamber is integrated above the reaction chamber and a vacuum hood is affixed over the flotation chamber. A vacuum nozzle device is connectable with a vacuum source and received through the hood and in the flotation chamber, a height adjustable foam intake provided at one end of the nozzle.

RELATED APPLICATION

This application is a Division of now pending U.S. patent applicationSer. No. 12/452,779 filed Jan. 22, 2010 by the inventor herein andentitled INTEGRATED VACUUM EVACUATION OF WASTE FOAM/GAS FROM ANELECTROCOAGULATION UNIT DURING EFFLUENT TREATMENT which priorapplication is a continuation of U.S. patent application Ser. No.11/888,512 filed Aug. 1, 2007 by inventors including the inventorherein.

FIELD OF THE INVENTION

This invention relates to effluent treatment, and, more particularly,relates to integrated vacuum evacuation of foam/gas from anelectrocoagulation unit.

BACKGROUND OF THE INVENTION

Most industrial and municipal processes require water treatmentfacilities to treat effluents returned to the environment. Suchfacilities typically represent a significant investment by thebusiness/community, and the performance of the facility (or failurethereof) can seriously impact ongoing operations financially and interms of operational continuity.

Moreover, not all effluent treatment requires the same technologies.Industrial effluents (such as is found at coal bed methane facilities oroil production sites, for example) all have different particulate,pollutant and/or biomass content inherent to both the industrialprocesses as well as the particular water and soil conditions found atthe site. Municipal requirements would likewise vary depending ondesired end-of-pipe quality and use (and again depending on the feedwater present at the site).

Electrocoagulation processes and foam/gas control processes inwastewater treatment are known. However, apparatus for performing suchprocesses have heretofore required extensive maintenance and investmentto assure proper operations, and have required extensive floor space fortheir installation. Moreover, some heretofore known apparatus have oftenrequired extensive monitoring to avoid accidental overflows betweenapparatus and/or have been inefficiently designed affecting both overalloperation of the apparatus and plant as well as apparatus longevity.

Therefore, improvement of such processes could still be utilized.Moreover, improved treatment technologies adapted to this and other usescan always be utilized given the criticality of provision andmaintenance of clean water.

SUMMARY OF THE INVENTION

This invention provides methods for vacuum evacuation of waste foam/gasfrom an electrocoagulation unit during effluent treatment. The methodsused reduce maintenance and plant investment costs and reduce plantinstallation space requirements. The methods enable improved stabilityand durability, and require more minimal monitoring to avoid accidentaloverflows and/or contamination.

The methods of this invention include the steps of positioning a vacuumnozzle having with a body and a height adjustable intake port at aprimary electrocoagulation unit reaction chamber so that the nozzle bodyis below or partly below fluid level thereat, and adjusting height ofthe intake port on the nozzle body so that the intake port is located inthe foam layer just above the fluid level. A vacuum is applied to thenozzle to remove foam and gas through the intake port.

The methods may more particularly include the steps of maintainingtreatment electrodes in the primary electrocoagulation reaction chamberand introducing effluent for treatment into the reaction chamber andwithdrawing treated effluent from the reaction chamber. A flotationchamber is integrated above the reaction chamber and above the fluidlevel with a hood located over the flotation chamber. Waste foam/gas isvacuumed in the flotation chamber through the nozzle body connectablewith a vacuum source and received through the hood in the flotationchamber. At least a partial vacuum is thus maintained at the flotationarea. Intake port height adjustment is achieved by positioning a shroudhaving a first intake port at one part of the nozzle body and rotatingthe shroud on the nozzle body to selectively adjust height of the intakeport thereby providing height adjustable waste foam/gas intake locationin the flotation chamber through the nozzle body. Vacuumed wastefoam/gas is output from the floatation chamber through the nozzle body.

It is therefore an object of this invention to provide methods forintegrated vacuum evacuation of waste foam/gas from anelectrocoagulation unit during effluent treatment.

It is another object of this invention to provide methods for integratedvacuum evacuation of waste foam/gas from an electrocoagulation unitduring effluent treatment that reduce maintenance and plant investmentcosts and reduce plant installation space requirements.

It is another object of this invention to provide methods for integratedvacuum evacuation of waste foam/gas from an electrocoagulation unitduring effluent treatment that provide stable and durable operationwhile requiring less monitoring to avoid accidental overflows and/orcontamination.

It is yet another object of this invention to provide a method forvacuum evacuation of waste foam/gas from an electrocoagulation unitprimary chamber including the steps of positioning a vacuum nozzlehaving with a body and a height adjustable intake port at the primarychamber so that the nozzle body is below or partly below fluid levelthereat, rotatably adjusting height of the intake port on the nozzlebody so that the intake port is located in a foam layer just above thefluid level, and applying vacuum to the nozzle to remove foam and gasthrough the intake port.

It is still another object of this invention to provide a method forvacuum evacuation of waste foam/gas from an electrocoagulation unitprimary chamber that includes the steps of maintaining treatmentelectrodes in a primary electrocoagulation reaction chamber andintroducing effluent for treatment into said reaction chamber andwithdrawing treated effluent from said reaction chamber, integrating aflotation chamber above said reaction chamber, locating a hood over saidflotation chamber, vacuuming waste foam/gas in said flotation chamberthrough a nozzle body connectable with a vacuum source and receivedthrough said hood in said flotation chamber, positioning a shroud havinga first intake port at one part of said nozzle body, rotating saidshroud on said nozzle body to selectively adjust height of said intakeport providing height adjustable foam intake location in said flotationchamber through said nozzle body, and outputting vacuumed waste foam/gasreceived through said nozzle body.

It is yet another object of this invention to provide a method forvacuum evacuation of waste foam/gas from a primary reactor chamber in aneffluent treatment electrocoagulation unit including the steps oflocating a flotation area above fluid level at the primaryelectrocoagulation reactor chamber, maintaining at least a partialvacuum at said flotation area, locating a vacuum nozzle device at saidflotation area and connecting said nozzle device with a vacuum source,and adjusting height of waste foam/gas intake location through saidnozzle device at said flotation area by adjusting a shroud having atleast a first intake port and mounted at one part of said nozzle deviceto control height of said intake port relative to said fluid level.

With these and other objects in view, which will become apparent to oneskilled in the art as the description proceeds, this invention residesin the novel construction, combination, and arrangement of parts andmethods substantially as hereinafter described, and more particularlydefined by the appended claims, it being understood that changes in theprecise embodiment of the herein disclosed invention are meant to beincluded as come within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate a complete embodiment of theinvention according to the best mode so far devised for the practicalapplication of the principles thereof, and in which:

FIG. 1 is a diagram illustrating facilities for application of effluenttreatment/sampling/testing processes;

FIG. 2 is a diagram illustrating components utilized in a treatmentsuite including electrocoagulation apparatus;

FIG. 3 is a sectional illustration of an electrocoagulation unitutilizable in the treatment suite;

FIG. 4 is a partial sectional illustration of the housing of the unit ofFIG. 3;

FIG. 5 is a partial sectional illustration showing apparatus providingprimary fluid head height level and foam/gas level control in theelectrocoagulation unit's primary reactor chamber; and

FIG. 6 is a perspective view showing portions of the hood and heightadjustable vacuum nozzle device employed for evacuation of foam/gas inthe reactor chamber of the electrocoagulation apparatus.

DESCRIPTION OF THE INVENTION

FIG. 1 shows effluent treatment apparatus (in this case a pre-treatmentsuite) 413. These include pH and chemical dosing apparatus 801 and 802,respectively, ODE/IDI membrane aeration apparatus 803,electrocoagulation apparatus 805, dissolved air/gas flotation 806,vacuum introduced cyclone separation apparatus 807, vacuum degassing808, lamella plate clarification 809 and sludge concentration output810. Additionally, eight testing nodes 811 through 825 are shown.

The primary function of pre-treatment suite 413 is the removal orsignificant reduction (exceeding 90%) of colloidal matter with totalsuspended solids, such as polysaccharides or other slimy matter, lessthan about 75 nm. In addition, removal or significant reduction (by 80to 90%) of fats, grease, oils and emulsions, and heavy metals (such asbarium, strontium and others) by 60 to 99% is achievable. Finally,removal of entrained and produced gas by vacuum down to residual levelsis achieved.

Regarding both ionized air/gas generation apparatus 804 and membraneaeration apparatus 803, improved ion treatment and reactor technologies,applications and methods of use are described. This aspect of theinvention relates to effluent treatment utilizing ionized air or gas andmembrane aeration, and has its objects, among others, enhanced ionizedgas transfer through known membrane aeration technology providing energyefficiency over conventional venturi technology. Using this technology,ionized gas transfer into feed water is further enhanced by means of astatic-in-line mixing comprising, for example, a progressive single coilsystem or an electrically charged dual coil system made from conductivebut non-sacrificial material such as synthetic graphite.

As will be seen, an integrated coil mixing system is convenientlylocated between a portion of the outer membrane side and the innerreactor wall of the liquid side. A gas ionization chamber is anintegrated part of the membrane support body. A radioactive energysource for gas ionization may be utilized, and is directly connected tothe ionization chamber thus minimizing occurrences of recombination ofion pairs prior to their diffusive transfer into the liquid phase.Transparency of the reactor's housing and coil support body allows forvisual inspection of the microbubble column and is controllable throughmeans of associated valving conveniently located on a reactor mountingpanel. The reactor's ionized air input is monitored and controlled bymeans of an in-line oxygen sensor and controller unit. The feed qualityis monitored and controlled by means of conductivity meters at theincoming feed and the outgoing treated water lines.

In order to affect a reasonable fallout rate of contaminants in thewater after electro-coagulation, it is necessary to add a chemicalpolymer prior to the electro-coagulation cell. If no chemical is added,fallout rates are unacceptably long. For a full size plant, this adds aburdensome financial component with respect to chemical costs and plantfootprint. Slow fallout rates translate into large tanks for increasedretention times.

Ionized air is a well recognized and employed technology in the field ofair purification. By creating a large number of negatively chargedoxygen ions and positively charged nitrogen ion, the ions then releasedinto the air where they attach themselves to floating particulate matterof opposing charge, heavier particles are created through chargeneutralization thus allowing them to fall to the ground effectivelyreducing airborne contaminants. The following teaches similar approachesat apparatus 803 and 804 of pre-treatment suite 413 for agglomerating,or coagulating, waterborne contaminants which are otherwise too small orincorrectly charged for easy removal.

Most waterborne contaminants in particulate form are charged. The chargecan be positive or negative, although most particles in certain postindustrial effluents (such as coal bed methane water) develop a negativecharge. When the particulate matter freely floats in water, they arecontinuously being repelled by each other, this repelling action makingthe particles difficult to agglomerate to form a more easily removablemass.

By introducing a stream of negatively and positively charged ions intothe water, one can effectively neutralize the particles specific chargesthus allowing them to be brought into intimate contact to form moreeasily precipitated matter. Once the interparticle repulsive forces havebeen neutralized, the fallout rate in and after processing byelectro-coagulation apparatus 805 will be enhanced and chemicaltreatment needs will be eliminated or drastically reduced. This processmight also speed up and enhance the iron and manganese precipitationprocess as well. Finally, these ions are also very disinfective toharmful biologic components present in some feed waters presented fortreatment and its holding tanks.

Membrane aeration apparatus 803 of pre-treatment suite 413 promotesradial mixing through means of an electrically chargedDualplex-start-Coil-System (DSC) mixing system. The DSC consists of twoindependent, non-touching coils with an even pitch spacing twistedaround the membrane. The coils are situated in the space between theoutside diameter of a membrane and the inside diameter of a supportbody. These coils are made of non-sacrificial, but conductive material,for instance graphite or graphite coated support material.

The proper non-touching spacing between the two coils is provided andsecured through a thinwalled duplex-start grooved support body, made ofclear nonconductive PVC. The duplex-starts in the support body areoffset to each other (i.e., turned by 180°). Pitch of each coil andgroove of one inch, providing a pitch distance of half an inch betweenthe two independent coils, suggest good performance for mostapplications. The coils are screwed into the support body concurrentlyand the support body is inserted as a cartridge into a reactor glassbody tube. The outer support body diameter is sealed against the bodytube (using O-rings, for example).

AC power is connected to the coil to provide for electrical connectionaway from the liquid phase. In essence this embodiment operates similarto an electrocoagulation system with non-sacrificial electrodes, theelectrically charged mixing coils representing the electrodes and thepitch spacing representing the electrode C-C distance. The operatingcurrent of the system is preferably 4 amps with a frequency convertersetting of between 1 and 10 hertz.

This unit can be employed with photo (UV) or other means of initiationof air ionization. For example, if radioactive initiated air ionizationis employed, the positively charged α-particles will deflect towards thenegatively charged electrical field. The frequency controlledalternating deflection of the α-particles takes place primarily withinthe upper portion of the ionization chamber. This alternating deflectionprovides additional collision potentials with the continual incominglarge number of neutral air molecules, thus slowing the recombination ofpositive and negative ion pairs prior to exposure to the contaminatedeffluent.

The alternating current flow provides an enhanced distributionenvironment for the diffusively aerated ionized air/gas for balancingthe surface charge of particles in the feed water solution thus removingor reducing the electrical repulsive charge on the particles. Thishydrodynamic mixing energy, provided through the differential pressureof the flow altering coil system, generates a turbulent fluid motionenvironment for interparticle contacts, sometimes called orthokinetikflocculation. The interparticle contacts of charge neutralized materials(for example, colloids) now destabilizes out of the dispersion, followedby collision of destabilized particles to form aggregates. Theaggregation of these particles into larger more easily settledaggregates is necessary for efficiency enhancement of followingprocesses where separation by precipitation, sedimentation and flotationtakes place.

FIGS. 2 through 4 show various other apparatus of treatment suite 413,FIG. 2 illustrating a particular arrangement thereof including the tenapparatus 801 through 810 heretofore identified configured with selectedpiping, flow control and instrumentation configuration. IDI inlineionizer unit 804 may be any known alpha ionizer such as the STATICMASTERseries form NRD and related instrumentation. Level sight glasses 2101and 2102 allow convenient on-site process inspection. Output from suite413 proceeds to stage 415 including a bag filter system 2105 and beltfilter system 2107.

In accordance with this invention, FIGS. 2 through 4 and the followingdescription illustrate the electrocoagulation apparatus andconfiguration in pre-treatment suite 413. Electrocoagulation apparatus805 operates conventionally but includes a number of unconventionalfeatures. In addition, apparatus 805 is positioned in tank 2111 (thelarger of the two tanks 2111 and 2113 separated by separator plate 2115)of lamella plate clarifier apparatus 809. Electrocoagulation operates bythe splitting off of ions from sacrificial electrodes, or utilization ofnon-sacrificial electrodes with native or added ions, in apparatus 805.The ions are thus introduced into the water presented for treatment todestabilize suspended, emulsified or dissolved contaminants in the waterby introduction of an electrical current. The water acts as an electricconductor in which current is carried, thus forming a hydroxidecompound. The most common sacrificial electrodes utilized in suchapparatus are made of iron or aluminum, the most common non-sacrificialelectrodes being made of carbon.

Present electrocoagulation art does not adequately address themechanisms of flotation, sedimentation and the circulation effect ofcoagulant aggregation in the early stages as bridging flocs. In theelectrocoagulation process, the partially lighter aggregated coagulantsare transported to the liquid surface by their attachment onto theascending electrolytic gas bubbles. The remaining, predominantlyheavier, aggregated coagulants bridge to heavier, larger flocs andprecipitate out into a sediment layer.

Treatment analysis in advance of establishment of the treatment regimendetermines the necessary mass quantity of matter that needs to bedeposited by the sacrificial electrodes. For diagnostic real timecapability, the electrocoagulation reactor described hereinafter may beequipped with selective multiple electrolytic cell choices (14 cells,for example) in the primary reactor chamber.

In accordance with this aspect of the invention, the following relatesto electrical apparatus for electrolytic flotation and electrochemicaldosing referred to as electrocoagulation, and apparatus, configurationsand methods for treating contaminated waters for selective pre-treatmentand/or cleaning of the waters. Electrocoagulation presents acost-effective alternative to traditional methods for treatment ofcertain polluted waters or as a method for the pre-treatment ofsuspensions, emulsions and light sludges prior treatment with membranetechnology, for instance clean up involving gas, dissolved and suspendedsolids removal from a hydraulic system where chemical or electrochemicaldosing, coagulation, electroflotation, flocculation and sedimentationwould be employed.

Apparatus 805 of this invention allows for a variety of electrodematerials to be implemented within one active electrode plate area fornumerous electrolytic treatment applications. The apparatus is compactand portable for easy delivery and hookup and is used in conjunctionwith the other apparatus for blending air, plasma-gas and/or dissolvedmetal salts with the feed water. As shown in FIG. 2, a plurality ofpumps for controlling the feed water flow and a plurality ofconveniently located valves, regulators and pump controls for automatedor manual control of the various functions of the apparatus 805 areprovided. Apparatus 805 is integrated directly with dissolved airflotation apparatus 806 in clarifier apparatus 809, and is furtherenhanced by integration with vacuum apparatus to accelerate theelectroflotation of the floc-foam layer to the liquid surface ofelectrocoagulation reactor (together referred to herein as “electrolyticdissolved air flotation”—EDAF—treatment).

The EDAF treatment approach utilizes a modified plate electrocoagulationreactor design. Because electrocoagulation reactor 805 is an integratedpart of clarifier tank 2111 of lamella apparatus 809, shear-free sludgetransfer in a compact single unit structure is provided. Vacuum enhancedelectroflotation is provided through the employment of an enclosedvacuum hood 2117 above flotation chamber 2119 of flotation apparatus806, to speed up the flotation process and as well remove unwantedcreated or entrained gases via vacuum degassing apparatus 808.

Vacuum hood 2117 is adjustable for proximity and vacuum lift capabilityto optimize the electroflotation effect as well as floc-foam surfacelayer removal at cyclone separator apparatus 807. Hood 2117 is mountedon outer housing 2121 holding inner reactor assembly 2123 ofelectrocoagulation apparatus 805. Inner assembly 2123 (FIG. 3) isdefined by four corner posts 2125 (FIG. 4) together establishing primaryreaction chamber 2127 and secondary reaction chambers 2129 and 2131adjacent the primary chamber. The secondary chambers provide additionalelectrocoagulation treatment stages to optimize the overallelectrocoagulation treatment on an as needed basis. Each secondarychamber includes an anode, cathode and bipolar electrode 2133, 2135 and2137, respectively, held in corner post 2139 for insulating thesecondary chambers as well as forming supports for insulating walls 2141of the primary chamber. A small jet of previously clarified processwater received through conduits 2142 washes electrode 2137.

Conical integrated sludge chamber 2143 is formed below primary reactionchamber 2127 and vacuum/flotation chamber 2119 of flotation apparatus806 is formed below chamber 2127. Primary electrode plates (eithersacrificial or, preferably, non-sacrificial) are held at a plurality ofelectrode positioners 2145 at opposed chamber walls. This electrodeframework allows rapid electrode interchangeability and/or electrode setups specially adapted to site circumstances. For example, a compositeelectrode setup with electrodes of different materials combined within asingle electrode stack could be utilized for treatment of complex feedwaters. Bipolar electrodes 2137 of secondary chambers 2129 and 2131 arereadily accessible for maintenance purposes.

Integrated sludge chamber 2143 provides buoyancy and/orelectromechanically actuated sludge transfer via a sludge cone valve2149. Sludge is transferred from sludge chamber 2143 into the fluid bedof the sludge holding/disposal chamber 810 at lamella clarifier tank2111 of clarifier apparatus 809, thus minimizing a shear introducinggradient to the delicate floc structure within the sedimentatedelectrocoagulation sludge. This eliminates or greatly reduces the needfor expensive floc polymers and/or coagulants as well as reducing energyrequirements for the floc rebuilding process. A compound sludge chamberangle of repose of 35° for hydroxide sludge is employed thus, inconjunction with a matching sludge cone release valve, preventing sludgebuild up within the chamber and expediting sludge release.

Float 2150 has a tap and valve arrangement 2153 at a suction lineprovided to allow weight adjustment by water addition to the floatcolumn or removal therefrom for trimming buoyancy of the float(wastewater removed is sent to cyclone unit 2155 to drain). Float 2150is balanced across pivot (P) against valve 2149 to actuate the valveactuating arm 2156 and open the valve when the weight of solids contentin chamber 2143 overcomes the buoyancy of float 2150. The resultantflush continues until head height equalizes and valve 2149 closes.

A variable discharge head and distribution system may be employed tominimize surface floc-foam layer carry over from the primary chamber andprovide suitable discharge distribution geometry into secondaryelectrocoagulation chamber(s), thus minimizing channeling and ensuringeffective electrocoagulation treatment in the secondaryelectrocoagulation. Secondary electrocoagulation flow control may beprovided through discharge disks and dampener adjustment to ascertainproper flow distribution, retention time and minimize channeling,providing an effective secondary and efficient overallelectrocoagulation treatment.

Multiple flat bar electrodes 2203 forming multiple electrode stacks 2205(only one shown in FIG. 3) are employed. These standard vertical stacksconsist of electrode bars 2203 arranged one on top of another.Horizontal stacks 2205 may be arranged with electrode bars 2203 in aside by side arrangement (instead on atop one another) and secured by atop contactor clip which also provides current transfer from one stack2205 to the next. The vertical multi-flat bar stack 2205 arrangement ismore suitable to maximize sacrificial electrode life. The sacrifice ofelectrode material is more pronounced on the leading edge/area of theascending feed water flow in a downward or upward directed parabolicshape. The leading edge problem can be minimized by substituting thebottom bar with a nonmetallic, but conductive graphite bar. Ifunacceptable, a new sacrificial bottom bar needs to be added from timeto time between whole stack replacements.

The vertical multi-flat bar option provides a mechanism for activeelectrode area reduction without sacrificing reactor retention time byinsertion of dielectric/nonconductive plate area (PVC or CPVC) into thevertical stack electrode structure in place of active electrode bar(s).This allows varying of the active surface area to volume ratio to findthe optimum ratio for a particular application. This variable ratiooption is an important feature in establishing scale-up of thisparameter.

Required electrical field strength (dependent upon concentration levelsand contaminant types in the feed water) can be manipulated by varyingelectrode C-C spacing for treatment optimization. Primaryelectrocoagulation facilities at 2127 are powered with a variablyapplied amperage in the range of 0.1 to 60 amps. With electrode bars setin series connection mode, the same current flows through all theelectrodes, and voltage is allowed to vary as electrocoagulationtreatment progresses over time.

A crossflow electrode flushing capability option through valve 2151 ispreferably provided to create a turbulent flow regime with the ascendingwater flow in primary electrocoagulation reactor chamber 2127 and withthe descending flow within the secondary electrocoagulation reactorchambers 2129 and 2131. Flow direction of flush water jetting isstaggered crosswise and perpendicular to the electrocoagulation processwater flow over the electrode plates. The directed turbulent flowcontinually washes the sides of the electrodes and prevents orsignificantly retards the build-up of impermeable oxide layers (passive)on the cathode as well as deterioration of the anode due to oxidation.This can be done instead of polarity switching or, in a fine regulatedmode, in addition to polarity switching in severe scaling situations orin applications that contain heavy amounts of grease or oils.

A small jet of previously clarified and pressurized process water flowis constantly or time sequentially introduced into theelectrocoagulation process water flow through a plurality small ( 1/32″,for example) holes drilled into electrode positioners 2145 at primaryelectrocoagulation reactor chamber 2127. Secondary electrocoagulationreactor chambers 2129 and 2131 have a plurality of similar holes 2142drilled into spaces at insulating corner post 2139 between and close tothe electrodes.

The three phase separation and removal areas of electrocoagulationreactor apparatus 805 operates as a standard parallel electrode unit (ina fluidized bed configuration a different arrangement would be applied).In phase one, light flotation solids in the floc-foam, gas (H₂ and O₂),and oil and grease layers are separated at the liquid surface andremoved by the adjustable vacuum at vacuum chamber 2119. In phase two,the semi-clarified effluent of the primary electrocoagulation treatedwater is separated from underneath the floc-foam surface layer atchamber 2127 and is removed or transferred through adjustable disk headcontrol devices into the secondary electrocoagulation reactor chambers2129/2131. It is here either optionally treated or directly dischargedinto the settling portion of the lamella clarifier tank 2111 to developclarity prior to discharge from the lamella separator 2115 overflow intothe clear flow catch tank 2113. In phase three, the solids precipitateout into integrated primary electrocoagulation sludge chamber 2143,proceeding through the normal sedimentation process mechanics.

When operating electrocoagulation apparatus 805 with non-sacrificialelectrodes, for instance with electrically conductive synthetic graphiteelectrodes, the necessary positively charged ions for maintaining theelectrocoagulation process are partially provided by the feed wateritself. The remaining part of the required positively charged ions areadded in form of metallic ions such as Al+, Ca+, Fe+ and Mg+ salts. Foran enhanced electron migration, the electrocoagulation process should beoperated within the acidic range through chemical dosing withhydrochloric (HCl), sulfuric (HS₂O₄) or phosphoric acid (H₃PO₄).Utilization of synthetic graphite electrodes avoids the consumption,replacement and operating down-time associated with conventionalsacrificial electrodes, and reduces energy and maintenance costs.Moreover, metallic salts are less expensive than the refined, finished,sawcut and otherwise machined or fabricated sacrificial metal electrodeplates. Varying the voltage controls the rate of electrochemicalactivity.

To facilitate effluent feed into chamber 2127, feed controller assembly2164 is provided (see FIGS. 2 and 3). A longitudinal tube 2165 ofassembly 2164 is connected with effluent feed line 2166 and has pluralelongated slots 2167 extending the length thereof (substantially theentire length of chamber 2127). Tube 2165 turns (for net feed areaadjustment) inside stationary 1¼″ base pipe 2169 having co-locatedelongated slots 2171 formed therealong. Turn adjustment of tube 2165thus defines net opening slot area defined by the selected overlap orslots 2167 and 2171, and thereby distributes the whole feed through theentire length of primary electrocoagulation reactor chamber 2127 (thusavoiding channeling and other distribution problems).

To facilitate foam/gas level control and discharge from inner reactorassembly 2123, and control primary fluid head level height in thereactor assembly, apparatus 2173 is provided for primary fluid headheight level and foam/gas level control in electrocoagulation unit 805'sprimary reactor chamber 2127 as shown in FIG. 5. Selectivelypositionable orifices 2175 of discharge weir disks 2177 are provided forflow control from chamber 2127 or into secondary chambers 2129 and/or

2131. To prevent surface foam carry over into the discharge or secondaryelectrocoagulation treatment chambers, a positive fluid head above thecenter of these orifices needs to be maintained at all times.

Head height is controlled by rotation of primary disks 2177 to locatefluid transfer orifices 2175 at selected positions (heights). The headheight in reactor chamber 2127 is higher than the surrounding fluidlevels in the secondary chambers 2129 and 2131 and in the clarifier tank2111. This higher level is instrumental in securing proper flushing ofsedimented solids out of the sludge chamber during automated flushingcycles.

Variable foam level control is achieved by fine adjustment of the areasof orifices 2175 in disks 2177 utilizing rotatable covers 2179 pivotablemounted on disks 2177. Covers 2179 are utilized for selectivelyrestricting flow through orifices 2175. In this way, fluid level heightwithin primary chamber 2127 is controlled well above the transferorifices' height, thereby avoiding transfer of foam on top of thechamber fluid through orifices 2175. Thus, foam and entrained oil,grease and other surface scum in primary chamber 2127 is retained inchamber 2127 for vacuum evacuation along with free gases as disclosedhereinafter.

Through simple contact plunger manipulation at an easily accessiblemultinode terminal bar or bars adjacent the electrodes (either manual orautomated contact manipulation could be deployed), electrocoagulationreactor operating circuitry can be arranged for different modes ofoperation. For parallel operation, contact plungers are provided at eachelectrode node at a terminal bar. This arrangement of theelectrocoagulation reactor circuitry provides parallel connection usingmonopolar electrodes. In this mode, the electric current is dividedbetween all of the electrodes in relation to the resistance of theindividual cells. The same voltage is present in all of the contactplungers. Varying the current controls the rate of electrochemicalactivity

For series operation, one contact plunger remains active at the terminalbar furthest from the source power connections. Insulated jumpersconnect the nodes. In this mode of operation the contactor terminal barprovides series connection for the monopolar electrodes in theelectrocoagulation reactor. In series cell arrangements, a higherpotential difference is required for a given current to flow, because ofhigher cumulative resistance. The same current would, however, flowthrough all the electrodes.

In a parallel, bipolar configuration (as shown in the secondary chambers2129 and 2131, but which could be applied primarily), one contactplunger at both contactor terminal bars remains, the one furthest fromthe source power connections. Only the monopolar anode and cathodeelectrodes are connected to the electrical power connections. In thismode, bipolar electrodes with cells in parallel are used. The bipolarelectrodes are placed between the two parallel anode/cathode electrodeswithout any electrical connections. When an electric current is passedthrough the two electrodes, the neutral sides of the conductive plate ofthe bipolar electrodes will be transformed to charged sides, which haveopposite charge compared to the parallel side beside it. This cellarrangement provides, where applicable, a desirable testing platform fora full scale unit application. Its simple set-up and maintenance canlower the overall electrocoagulation operating cost.

A mixed parallel and series configuration could be provided, providingindividual mixed cell circuitry configurations. For instance, in afourteen cell reactor, half the cells could be connected in a seriescircuitry and the remaining seven cells connected in parallel, either asmonopolar, bipolar or in mixed mode. This option can be used as adiagnostic tool when different amperages are needed for differentelectrode materials within the primary electrocoagulation reactor forspecific treatment situations.

These parallel or series power connection choices are implemented byspring loaded contactor bars with integrated connectioninterchangeability (plungers). DC or AC operating power options withvariable current density controls are implementable for control ofelectrochemical dosing and electrolytic bubble density production forsacrificial electrodes, as well as regulating the required transportcurrent for the required added positively charged ions when nonmetallicand non-sacrificial electrodes are employed.

Controlled polarity switching for DC power implementations is providedto prevent or minimize oxide build up as well as hydrogen polarization.A vector frequency controller for the AC power option provides forfrequency control below 60 Hertz to prevent disaggregation ofagglomerated particles. To accommodate rapid changes of electrodesand/or customization of electrode setups, main power distributionthrough removable, quick release, swing away main contactor bars,providing as well for rapid change from parallel to series powerconnection, is utilized.

Regarding pre-treatment suite stages 411 and 413, zeta potential is animportant part of the electrokinetic phenomena of interaction betweenparticles in suspension. The zeta potential is the electrokineticpotential of a suspended particle as determined by its electrophoreticmobility. This electric potential causes colloidal particles to repeleach other and stay in suspension. The zeta potential is a measurementof the overall charge characteristic of the suspended particles in thewater. The kind and magnitude of the electrical charge depends on thesurface potential of the particles, or the zeta potential. A negativezeta potential indicates that the water contains free negatively chargedsuspended solids (common in many treatment feed waters) that arestabilized and therefore more likely to stay in solution.

A neutral zeta potential indicates that the suspended solids do notcarry a charge to assist in their electrical repulsion of each other.They are more likely to destabilize and coagulate into largerparticulate groups and fall out of solution, and therefore being removedas part of the pre-treatment. The importance of the zeta potential restson the fact that it can be measured experimentally and in many casesserves as a good approximation of the unmeasurable surface potential ofthe colloidal particle, since there is a fairly immobile layer ofcounter ions that sticks tightly to the surface of the particle.Treatment diagnostics herein thus uses the zeta potential measurement togauge coagulant requirements (if any), and can be adapted for automatedadjustment of an injected cationic (positively charged) coagulant suchas reverse osmosis Quest 6000, which could be used in pre-treatmentstage 411, to achieve a neutral zeta potential upstream of pre-treatmentstage 413. Thus utilized, suspended solids would be more likely to fallout of solution into 2111 of clarifier 809.

Filtration stage 415 (step 7) makes use conventional know bag filtersystems 2105 and or belt filtration systems 2107 (such as theRoll-A-Filter or Lazy Filter fabric media systems produced by SERFILCO.

Vacuum introduced cyclone separation apparatus 807 of suite 413 (FIG. 2)utilizes a conventional cyclone unit or units 2155 and 2157 connectedfor vacuum inducement apparatus 808 and hood 2117 and outlet for foamcollection through filters 2159 and 2161, respectively.

FIG. 6 illustrates the functions of vacuum inducement apparatus 808 andhood 2117 for vacuum evacuation of foam/gas retained in reactor (orreaction) chamber 2127 of electrocoagulation unit 805. Height adjustablevacuum nozzle device 2601 is located in flotation chamber 2119 and ismounted through vacuum hood 2117 (preferably made of clear LEXAN).Nozzle device 2601 is provided with vacuum suction from either a vacuumpump or venturi arrangement. Suction inline cyclone unit 2155 separatesthe major portion of the wet surface foam from the gas phase.

Nozzle device 2601 includes nozzle body 2603 and a rotatable inlet portshroud 2605 mounted at the end of body 2603. Vacuum stem pipe 2607 has alength selected to position nozzle body 2603 below or partly below fluidlevel. Shroud 2605 is adjustable so that foam intake slots 2609 at theouter circumference of shroud 2605 are located in the foam layer andabove the fluid level thus avoiding vacuum intake of fluid whileallowing evacuation of the foam layer between the electrode plate andthe area with primary chamber 2127.

Adjustable vacuum relief valve 2610 is set appropriately to avoid damageto the unit. A suction line includes adjustable valve 2153 to trim thelevel in float 2150 and collected foam is sent to cyclone unit 2155though port 2611. Vacuum level is controlled at adjustment valve 2613.Excess air from aeration processing at membrane aeration apparatus 803is received though port 2615.

Air (from ionized air/gas generation apparatus 804 and/or membraneaeration apparatus 803) dissolved into the fluid entering unit 805diminishes the solids carrying capacity of fluid in unit 805, thusexpediting the precipitation of solids from the fluid and enhancing foamcreation floating the lighter solids and oils to the surface forevacuation.

As may be appreciated from the foregoing, apparatus and methods forintegrated vacuum evacuation of waste foam/gas from anelectrocoagulation unit are provided. The apparatus and methods helpreduce maintenance and plant investment costs and plant installationspace requirements, and provide stable and durable operation withminimal monitoring to avoid accidental overflows and/or contamination.

What is claimed is:
 1. A method for vacuum evacuation of waste foam/gasfrom an electrocoagulation unit primary chamber comprising the steps of:maintaining treatment electrodes in a primary electrocoagulationreaction chamber and introducing effluent for treatment into saidreaction chamber and withdrawing treated effluent from said reactionchamber; integrating a flotation chamber above said reaction chamber;locating a hood over said flotation chamber; vacuuming waste foam/gas insaid flotation chamber through a nozzle body connectable with a vacuumsource and received through said hood in said flotation chamber;positioning a shroud having a first intake port at one part of saidnozzle body; rotating said shroud on said nozzle body to selectivelyadjust height of said intake port providing height adjustable foamintake location in said flotation chamber through said nozzle body; andoutputting vacuumed waste foam/gas received through said nozzle body. 2.The method of claim 1 further comprising locating at least a second foamintake port opposite said first foam intake port at said shroud.
 3. Themethod of claim 2 further comprising configuring said ports as elongatedslots.
 4. The method of claim 1 further comprising separating wet foamfrom gas phase after outputting vacuumed waste foam/gas.
 5. The methodof claim 4 wherein the step of separating wet foam from the gas phasefurther comprises cyclonic separation at a unit connected to receiveoutput waste foam/gas.
 6. The method of claim 1 further comprisingselectively locating said nozzle body in said chambers so that saidnozzle body is below or partly below fluid level at said flotationchamber with said shroud intake port adjustably positionable in a foamlayer just above the fluid level.
 7. The method of claim 1 furthercomprising selectively adjusting vacuum level applied at said chambers.8. The method of claim 1 further comprising selectively controlling headheight and foam/gas level at said flotation chamber.
 9. A method forvacuum evacuation of waste foam/gas from a primary reactor chamber in aneffluent treatment electrocoagulation unit comprising the steps of:locating a flotation area above fluid level at the primaryelectrocoagulation reactor chamber; maintaining at least a partialvacuum at said flotation area; locating a vacuum nozzle device at saidflotation area and connecting said nozzle device with a vacuum source;and adjusting height of waste foam/gas intake location through saidnozzle device at said flotation area by adjusting a shroud having atleast a first intake port and mounted at one part of said nozzle deviceto control height of said intake port relative to said fluid level. 10.The method of claim 9 further comprising selectively controlling headheight and foam/gas level at the reactor chamber.
 11. The method ofclaim 9 further comprising selectively locating said vacuum nozzledevice at a position below or partly below said fluid level at thereactor chamber.
 12. The method of claim 9 further comprising locatingat least a second foam intake port opposite said first foam intake portat said shroud.
 13. The method of claim 12 wherein the step of adjustingheight of waste foam/gas intake location includes rotating said shroudon a nozzle body of said nozzle device to control height of said intakeports.
 14. A method for vacuum evacuation of waste foam/gas from anelectrocoagulation unit primary chamber comprising the steps of:positioning a vacuum nozzle having with a body and a height adjustableintake port at the primary chamber so that the nozzle body is below orpartly below fluid level thereat; rotatably adjusting height of theintake port on the nozzle body so that the intake port is located in afoam layer just above the fluid level during processing; and applyingvacuum to the nozzle to remove foam and gas through the intake port. 15.The method of claim 14 further comprising adjusting head height and foamlayer level at the chamber.
 16. The method of claim 14 furthercomprising receiving removed foam/gas from the intake port andseparating wet foam from the gas phase.
 17. The method of claim 14further comprising adjusting vacuum level applied to the nozzle.
 18. Themethod of claim 14 wherein the step of rotatably adjusting height of theintake port includes rotation of a shroud on the nozzle body, the shroudhaving said intake port thereat.